Various types of sling chairs have been known which provide a somewhat concave and/or giving backrest. Such chairs generally include a back portion and a seat portion, and may optionally include armrest portions. The back portion generally includes a back frame and a flexible yet supportive backrest made of fabric or other suitable material and mounted to the back frame. Different mechanisms have been employed for securing the backrest to the back frame, and these prior art mechanisms have suffered from several deficiencies. First, these prior art mechanisms often fail to provide a secure connection, which can result in the backrest being unsupportive of the seated individual. Second, sling chairs often expose aspects of the sling hardware, such as attachment elements or fasteners, and it would be aesthetically desirable to hide such aspects. Further, the sling backrest for these chairs is frequently retained along the chair side rail supports, creating side-to-side sling tension, restricting the potential to add decorative chair features, and complicating assembly.